|Publication number||US7431093 B2|
|Application number||US 11/439,409|
|Publication date||Oct 7, 2008|
|Filing date||May 23, 2006|
|Priority date||Sep 30, 2002|
|Also published as||CA2440927A1, CA2440927C, US7048057, US20040060707, US20060207759|
|Publication number||11439409, 439409, US 7431093 B2, US 7431093B2, US-B2-7431093, US7431093 B2, US7431093B2|
|Inventors||John L. Bearden, Jerald R. Rider|
|Original Assignee||Baker Hughes Incorporated|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (23), Referenced by (1), Classifications (12), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is a continuation of and claims the benefit of U.S. patent application Ser. No. 10/260,706 entitled PROTECTION SCHEME AND METHOD FOR DEPLOYMENT OF ARTIFICIAL LIFT DEVICES IN A WELLBORE filed Sep. 30, 2002 which will issue into U.S. Pat. No. 7,048,057 on May 23, 2006.
1. Field of the Invention
This invention relates generally to submersible artificial lift devices, and in particular to a single or multi-device system provided with a barrier to deter an ingress of well fluids into the device to reduce or prevent development of corrosion, formation of scale or asphaltenes or other problems in an idle device within a wellbore.
Submersible artificial lift devices are widely used to pump fluid from a wellbore, particularly for purposes of hydrocarbon recovery. Examples of submersible artificial lift devices include an electrical submersible well pump (ESP) and an electrical submersible progressing cavity pump (ESPCP). Typically, an artificial lift device is suspended within a well from a flow conduit. The artificial lift device is submerged in well fluids. Prolonged inactivity and exposure to well fluids may damage motor and pump components of a typical artificial lift device. Therefore, it is desirable to protect the internals of an inactive artificial lift device when the device is submerged in wellbore fluids.
For example, U.S. Pat. No. 2,783,400 to Arutunoff teaches a protecting unit for an oil field submergible electrical motor. The protective unit provides a pathway for a lubricating and protecting fluid to expand or contract as a result of heating or cooling due to the electric motor. Additionally, the protecting unit essentially doubles the length of a path traveled by moisture or any contaminating fluid before such fluid can reach the pumping unit. One potential drawback of the protecting unit of Arutunoff is that the lengthened moisture path delays rather than prevents moisture migration to the pumping unit.
In some cases, it has been desirable to deploy multiple pumping units within a wellbore. Examples of multiple pumping units include the following:
U.S. Pat. No. 3,741,298 to Canton teaches a multiple well pump assembly wherein upper and lower pumps are both housed in a single wellbore hole and the pumps are connected in parallel so as to supplement each other's output. The pumps may be provided with different flow capacities and may couple with power means for running each pump individually or both simultaneously to provide a well pump system capable of selectively delivering three different effective flow rates from a single wellbore hole to satisfy varying flow demands.
U.S. Pat. Nos. 4,934,458 and 5,099,920 to Warburton et al. teach a small diameter dual pump pollutant recovery system. The system includes a water pump assembly and a pollutant pump assembly mounted at the lower end of piping, which serves to suspend the pumps in a well and also as an exhaust conduit for transporting pump water to the surface. The pollutant pump is used to recover lower density immiscible pollutants from the surface of the underground water table using the cone of the pressure method. The water pump may be raised and lowered to the position at the pollutant/water interface. A method of relocating the pollution intake and resetting the height of the cone of depression when conditions vary the height of the pollutant/water interface is also disclosed.
U.S. Pat. No. 5,404,943 to Strawn teaches a multiple pump assembly for wells. Strawn teaches a design to allow multiple submersible pumps in a single borehole. The multiple pump assembly provides flexibility in use of multiple pumps by allowing the user to avoid multiple well requirements through the use of standby or peak loading pumps.
U.S. Pat. No. 6,119,780 to Christmas teaches a wellbore fluid recovery system and method for recovering fluid from a wellbore that has at least one lateral wellbore extending out therefrom. The system includes a first electrical submergible pumping system for recovering fluids from a first zone of a wellbore and a second electrical submergible pumping system for recovering fluids from a second zone of a wellbore, such as a from a lateral wellbore. The fluid recovery system allows fluid recovery from each lateral wellbore to be independently controlled and also to provide adequate draw down pressure for each lateral wellbore.
U.S. Pat. No. 6,250,390 to Narvaez et al. teaches a dual electric submergible pumping system for producing fluids from separate reservoirs. A first submergible pumping system is suspended from deployment tubing and a second submergible pumping system is suspended from deployment tubing. The first submergible pumping system is connected to a fluid transport such that fluid may be discharged into the first fluid flow path, and a second submergible pumping system is connected to the fluid transport such that the fluid may be discharged into the second fluid flow path.
Typically, once an ESP is located below the static fluid level during deployment of the ESP into the well, wellbore fluid is free to enter into and fill the pump. If a blanking plug is installed, e.g. in a Y-Tool crossover, wellbore fluid is free to fill the open path in the pump and compress the air cap in the pump having a blanking plug in place. Depending on submergence pressure, the wellbore fluid may partially or substantially fully fill the pump.
A difficulty with having an idle unit that is at least partially filled with well fluid is that the idle unit is subject to the possibility of degradation of internal components including scale or asphaltenes precipitating out in the unit, which can cause either plugging of flow passageways and/or interference or locking of rotating components. Therefore, it is desirable to provide a protective environment for internals of the pump(s) that are held in backup or that have a delayed start-up. A protective environment increases the reliability of starting and running the pumps.
The present invention features an artificial lift device that is suspended on a flow conduit within a well. The artificial lift device is submerged in well fluids. A barrier is provided to prevent ingress of well fluids into the artificial lift device.
In many instances it is desirable to use multiple artificial lift devices in a single borehole. One advantage is that one device may be used as a primary pump and a second device may be used as a backup pump. One difficulty is that the static, or backup, unit sits idle and soaks in the wellbore environment, where the backup unit may be exposed to pressure cycles and possibly small temperature cycles. Possibilities exist for scale or asphaltenes to precipitate out in the unit. This can cause plugging of flow passageways and/or interference or locking of rotating components. By providing a barrier to protect the internal components of a backup unit or units from well fluid, the probability of damage to internal components is reduced.
In one embodiment, a multi-unit system of the invention is suspended on a tubing string into the wellbore. The multi-unit system has a junction, such as a Y-tool, T-connector or other type of junction having an upper end that communicates with production tubing and has a lower end having an operating unit port and a backup unit port. An operating unit communicates with the junction via the operating unit port and a backup unit communicates with the junction via the backup unit port. A barrier, such as a valve, blanking plug or other type of barrier is provided in the junction for selectively blocking off either the operating unit port or the backup unit port, thereby blocking fluid communication with either the operating unit or the backup unit. The backup unit is also provided with an intake barrier that deters ingress of well fluids into the backup unit. Therefore, the backup unit may remain submerged within well fluids for an extended period of time without experiencing degradation of the backup unit internals. The intake barrier may include a plug, burst disk, soluble material, a selectively openable intake barrier such as a sleeve or a spring biased member or other member that is capable of providing a suitable barrier.
In one embodiment, a pressure sensor is provided in communication with the interior of the backup unit. The pressure sensor communicates with a pressure producing device, such as a compressor, pump, or other device that may be activated to maintain a positive pressure within the backup unit to assist in preventing well fluids from entering the backup unit. A pressure sensor may also be provided in communication with the interior of the primary unit to detect a failure of the primary unit and to send a signal to an automated system to auto-activate the back-up unit. Alternatively, the pressure sensor may be used to send a warning to the surface, e.g., to a workstation, so that an operator may intervene to take appropriate action, such as starting the back-up unit in the event of primary unit failure.
The invention further includes a method of preserving pump integrity of an idle unit in a well, e.g., as a backup unit in a multiple unit system in a common wellbore. The method includes locating a multi-unit system in a wellbore wherein the multi-unit system includes an operating unit in communication with a junction and the backup unit in communication with a junction. A fluid barrier is provided in an output port output passageway, the junction, an intake port, or both ports or other combination of locations to deter ingress of well fluids into the backup unit. The backup unit is preferably filled with a protective fluid. The backup unit may be filled with protective fluid prior to deploying the multiple unit system within the wellbore or the backup unit may be filled, e.g., via a hydraulic communication line after the multiple unit system is deployed within the wellbore.
In one embodiment, a bubbler gage system may be used to deliver a fluid, such as an inert gas, to the backup unit. Typically, a bubbler gage system includes a fluid line extending from the surface to a location below the fluid level in a well, in this case to a submerged artificial lift unit. Fluid is then continuously delivered to the interior of the unit to maintain a positive pressure therein, which deters ingress of fluids into the unit. The bubbler gage also provides an additional benefit in that the well fluid level may be determined by noting when the pressure required to deliver additional fluid into the fluid line ceases to increase as a function of volume of fluid delivered.
To facilitate operation of the idle unit, the barrier is removed. The barrier may be removed by the application of additional pressure in the backup unit to push out a barrier or to burst a burst disk type barrier or by activating the unit to “pump out” a barrier. Additionally, if the barrier is comprised of a soluble material, then a solvent may be delivered to the backup unit to dissolve the fluid barrier. A selectively openable member may also be activated to open a flapper type valve, to slide a sliding sleeve, or to manipulate other types of selectively openable members. Examples of activators include, but are not limited to, a hydraulic line, an electric line in communication with a servo or an electric line to deliver a one time electrical pulse to activate a charge, a pneumatic line, or other means. Further, the barrier may be a spring-biased member that opens automatically by activation of the backup unit. Additionally, the barrier may be activated to open by rotation of the shaft in the unit. The barriers may also be opened to allow the fluid barrier to drain or flow out of the unit. Other types of barriers may also be used. Although the invention is described primarily as it relates to a protection scheme for a backup unit, it should be understood that the invention is also applicable to a single ESP unit that is to remain idle for a period of time while submerged in well fluids.
A better understanding of the present invention, its several aspects, and its advantages will become apparent to those skilled in the art from the following detailed description, taken in conjunction with the attached drawings, wherein there is shown and described the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated for carrying out the invention.
Before explaining the present invention in detail, it is important to understand that the invention is not limited in its application to the details of the embodiments and steps described herein. The invention is capable of other embodiments and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.
Referring now to
Referring back to
The multiple unit system 10 of the invention is provided with a second unit 60, which may be used as a primary unit or as a back-up unit as desired. Second unit 60 communicates with the second unit port 34 of Y-Tool 26 via a second unit passageway 62. Second unit passageway 62 communicates with discharge port 61 of second unit 60. The second unit 60 and the second unit passageway 62 are preferably affixed to the first unit 42 via a series of clamps 64. As shown, second unit 60 is an ESPCP having a progressing cavity pump 66, a flex shaft section 68, a seal section 70, a gear reducer 71 and an electric motor 72. The electric motor 72 receives power from the surface via a cable. Second unit 60 is also provided with a fluid intake 74.
It should be understood that although
Referring now to
Examples of intake barrier 100 include plug 108 (
In practice, a method of preserving pump integrity of an idle unit, such as second unit 60 of a multiple unit system 10 is as follows. It should be understood that the method of preserving pump integrity is equally applicable to first pump 42 or to a stand alone artificial lift device, secondary back-up unit or other artificial lift device and that second unit 60 is used herein for purposes of example only. An intake barrier 100 is provided in pump intake 74 of the second unit 60 to deter ingress of well fluids 18 into the second unit 60. The second unit 60 is filled with a protective fluid to inhibit contamination of the second unit 60 within the wellbore 12. Examples of suitable protective fluids include but are not limited to a range of fluids having a generally lighter specific gravity, e.g. diesel, to protective fluids that have a generally heavy specific gravity, e.g. “Beaver Lube”. Preferably, the protection fluids are inert with respect to component materials of the unit. Second unit 60 may be filled with protective fluid prior to deployment of multi-unit system 10 within the wellbore 12 or may be filled with protective fluid via hydraulic communication line 106 after multiple unit system 10 reaches setting depth. In one embodiment, pressure within the second unit 60 is at least periodically maintained at a level that is equal to pressure external of the second unit 60 in the wellbore. Pressure within the second unit 60 may be maintained via hydraulic communication line 106, which is operatively connected to a pressure producing device, such as compressor 104. Additionally, periodic flushing of the second unit 60 may be undertaken to assure continued protection over the time.
If a protective fluid is used that has a heavier specific gravity than well fluids, then the unit 60 may be sealed with an intake barrier 100 since the protective fluid will tend to settle to the lower portions of the unit. Conversely, if a protective fluid is used that has a lighter specific gravity than well fluids, then a barrier may located in the junction 23, as shown in
In operation, if an operating unit, e.g. first unit 42, fails or if it is desired to run first unit 42 and second unit 60 simultaneously, an intake barrier 100 and/or output barrier 35 must be removed from the pump intake 74 and/or the output region of the second unit 60. Similarly, if unit 60 is a stand alone unit in a well, e.g., if for some reason it is desirable to install the unit 60 and leave the unit idle for some period of time, then intake barrier 100 and/or output barrier 35 will be removed from pump intake 74 before operating unit 60.
One method of removing an intake barrier is to apply additional pressure within the backup unit 60 via hydraulic line 106 to push out the intake barrier 100, such as plug 108 (FIG. 4). Additionally, pressure may be delivered to the second unit 60 via hydraulic line 106 to burst a burst disk 110 (
Further, in one embodiment, intake barrier 100 and/or output barrier 35 may be a soluble plug 114 (
Although, second pump 60 has been shown as part of a multi-unit artificial lift system 10, the protection schemes of the invention could be utilized on multi-unit artificial lift systems having multiple backup pumps or the protection schemes of the invention could be utilized on a single artificial lift device deployed downhole, particularly where the single artificial lift device may not be started immediately.
Referring now to
A shroud 218 surrounds the upper artificial lift device 206. Shroud 218 defines an annulus 220 between the upper artificial lift device 206 and the shroud 218. An upper closure member 222 is positioned on an upper end of shroud 218. The upper closure member 222 preferably has a first electric cable aperture 224 and a second electric cable aperture 226. A first cable 228 extends down through wellbore 204 through the first electric cable aperture 224 and provides power to the upper artificial lift device 206. A lower closure member 230 is provided on the lower end of shroud 218. The lower closure member 230 preferably has an aperture 232 located therein. The upper closure member 222 and the lower closure member 230 seal off ends of annulus 222 and define a sealed annular space 234.
A lower artificial lift device 236 is located below the upper artificial lift device 206. Lower artificial lift device 236 has an input port 238 that it is in communication with wellbore fluids in wellbore 204. Lower artificial device 236 additionally has an output port 240. The output port 240 is in communication with the aperture 232 and the lower closure member 230. Preferably, a passageway 242 communicates the output port 240 of the lower artificial lift device 236 with the annular space 234 by passing through aperture 232 in the lower closure member 230. Passageway 242 is additionally provided with a lower selectively openable member 246, which may be of the type described above with respect to upper selectively openable member 214. A second electric cable 250 extends through the second electric cable aperture 226 in the upper closure member 222. The second electric cable extends within annular space 234 and provides power to the lower artificial lift device 236. Second electric cable 250 may also extend through an aperture in lower closure member 230 similar to second electric cable aperture 226 in upper closure member 222, as required.
In operation, lower artificial lift device 236 may be provided with intake barriers 100 (
If upper artificial lift device 206 fails, or if it is desirable to run lower artificial lift device 236 while using upper artificial lift device 206 as a backup, then upper selectively openable member 214 is opened to allow wellbore fluids to pass therethrough. In this mode of operation, lower artificial lift device 236 intakes wellbore fluids through input ports 238. The wellbore fluid is driven out of output port 240 and through passageway 242 into the annular space 234 between the shroud 218 and upper artificial lift device 206. The wellbore fluid then flows past the upper artificial lift device 206 and through the open selectively openable member 214 and through passageway 212 and into tubing 202 where it can pass through the surface. Advantages of the POD system 200 include the ability to install dual or multi-unit systems in well casing having a smaller diameter as compared to multi-unit systems utilizing a junction, as shown in
While the invention has been described with a certain degree of particularity, it is understood that the invention is not limited to the embodiment(s) set for herein for purposes of exemplification, but is to be limited only by the scope of the attached claim or claims, including the full range of equivalency to which each element thereof is entitled.
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|U.S. Classification||166/372, 166/105, 166/316, 166/242.3, 166/332.8, 166/106|
|International Classification||E21B41/02, E21B43/12|
|Cooperative Classification||E21B43/128, E21B41/02|
|European Classification||E21B41/02, E21B43/12B10|
|Aug 28, 2007||AS||Assignment|
Owner name: BAKER HUGHES INCORPORATED, TEXAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BEARDEN, JOHN L.;RIDER, JERALD R.;REEL/FRAME:019757/0647;SIGNING DATES FROM 20070822 TO 20070827
|Apr 9, 2012||FPAY||Fee payment|
Year of fee payment: 4
|Mar 23, 2016||FPAY||Fee payment|
Year of fee payment: 8